1. Field of the Invention
The present invention relates generally to the field of semiconductor technology. More particularly, the present invention relates to a method for fabricating a power semiconductor device with super junction structure.
2. Description of the Prior Art
As known in the art, super junction power MOSFET devices include alternating p-type and n-type regions below the active regions of the device. The alternating p-type and n-type regions in a super junction power MOSFET device are ideally in charge balance so that those regions deplete one another under a reverse voltage condition, thereby enabling the device to better withstand breakdown.
It is known to utilize super junction structures in trench type power devices. To form such trench type super junction power devices, typically, deep trenches are etched into a main surface of a semiconductor substrate, and an epitaxial layer is then formed to fill the deep trenches. However, the prior art fabrication method has drawbacks. For example, the surface concentration of the dopants driven into the trench surfaces is too high. This leads to non-uniformity of the carrier concentration distribution.